Generally, electric furnaces are devices which manufacture steel in such a way that raw materials such as iron ore are melted and refined by arc heat generated between a plurality of electrode rods and scrap when current is applied to the electrode rods.
In such an electric furnace, the roof which covers the electric furnace is opened, and raw material such as scrap is put into the electric furnace by a crane or the like. Thereafter, high voltage is applied to the electrode rods that are vertically connected to the roof after the roof covers the upper end of the electric furnace. Then, the raw material is melted by high-temperature arc heat. Molten steel which is formed by melting the raw material such as scrap iron is transferred into a teeming ladle through an outlet hole formed in a lower portion of the electric furnace. The teeming ladle filled with molten steel is transferred to a place for another process by a transport carrier.
The above-mentioned roof effectively blocks and discharges a large amount of fumes which are generated in the electric furnace during the process of melting scrap or the like that has been put into the electric furnace. Also, the roof prevents noise from occurring during the melting process and blocks splash slag from scattering out of the electric furnace.
An example of the prior art was proposed in Korean Utility Model Publication No. 1983-0003259 (Publication date: Dec. 12, 1983, title: Arc type electric furnace ceiling having extended lifetime).